Factorise 3a2-4ab please

The polygon tool to draw a rectangle with a length of 5 units and a height of 3 units. one of the sides of the rectangle falls on line ab , and the rectangle has a vertex of a. each segment on the grid represents 1 unit.

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

This is the number of parts out of 100, the numerator of a fraction where the denominator is 100. submit